Compression Ratio of a EJ20H block + SS Heads

[BXSS]

The motor in the wife's OBS is getting pretty up there in mileage, so I was thinking of possible replacements.
I have a set of SOHC SS heads with just over 100k on them + a EJ20H block with about 60K on it that I was thinking of putting together for a freebie motor.

I know with stock DOHC heads the EJ20H is supposed to have 9:1 C/R, but what would the C/R of the EJ20H block be with SS heads?

[Matt Monson]

Here's a couple of threads to get you going...

http://bbs.legacycentral.org/viewtopic. ... ght=hybrid

http://bbs.legacycentral.org/viewtopic. ... ght=hybrid

Given that the EJ20H uses heads with a smaller combustion chamber than the Ej20G Legacy engine, I suspect yours would be in the high 9's, maybe even over 10:1. I don't know that it would be a good turbo option, but if you just used her NA heads with it, it would probably be a decent NA engine.

[BXSS]

Thanks!

[BXSS]

I read that the combustion chambers of EJ20Gs & EJ20Ks are the same & I always hear that EJ20K's & EJ20H's are the same basic head so I'm confused as heck right now...

I was thinking a CR of about 9.5:1 but have never compared the EJ20H & EJ20G heads to each-other side by side....

I'm not trying to boost a TD04 past 5psi on her motor but do not want something too stressed either

Am I way off on the CR info / numbers?

[BXSS]

Had a fun day today & cracked open a EJ20H Freebie block I got from a friend + a blown EJ20G block for another friend & the pistons look to be the SAME on both blocks!

The exhaust ports on the EJ20H are SMALLER than WRX EJ20G e-ports - did not really compare intake ports but I should have...